Joint synchronization of symbol timing and carrier frequency using the extended zero-crossing property

Coarse recovery of carrier frequency and symbol timing in multibeam satellite channels

“…Since data, carrier phase, and timing are not known to the receiver at this stage of processing, the related synchronizer module has to be run in a non‐data‐aided and phase‐independent manner by using an oversampled version of the receiver signal. Doing this also for the symbol timing and obtaining this goal by a joint feedback (FB) loop, we end up with an architecture illustrated in Figure , which has already been suggested in Gappmair et al for a single user link and which will be described subsequently in more detail.…”

“…On the other hand, the error signals feeding the filters are available at the output of the frequency error detector (FED) and the timing error detector (TED), respectively. They are straightforwardly computed as and …”

“…() Motivated by this background, we want to study in the following an algorithm for coarse recovery of carrier frequency and symbol timing in a multibeam downlink channel. In particular, the tracking and acquisition performance of the joint synchronization scheme, developed in Gappmair et al for a single user link, is to be investigated under multibeam conditions.…”

Joint recovery of carrier frequency and symbol timing for extremely bandwidth‐efficient satellite links

“…In this context, a feedback (FB) solution for joint recovery of carrier frequency and symbol timing has been suggested in [3]. Although the jitter variance of the residual frequency error turned out to be rather high compared to the modified Cramer‐Rao lower bound (MCRLB) as the theoretical limit in this respect [4–7], this sort of coarse frequency control avoids that user signals are distorted by the receiver matched filter (MF) in case of larger frequency offsets.…”

“…In order to circumvent any jitter floor with respect to frequency and timing recovery, a filter operated in parallel to the MF had been proposed in [3], characterised by the so‐called extended zero‐crossing (XZC) property, i.e. the impulse response of the parallel filter concatenated with the pulse shaping filter in the transmitter is zero at all integer multiples of the symbol period, including the origin [10].…”